[ Java 代碼範本 ] 取得系統記憶體, CPU 相關使用資訊

參考自 這理
前言 :
最近做個項目，就是要取得cpu佔有率等等的系統信息，一開始以為要用動態鏈接庫了，但後來發現可以像下面這樣做，不去調用jni，這樣省去了很多JNI 所帶來的 effort. 在Java中，可以獲得總的物理內存、剩餘的物理內存、已使用的物理內存等信息，下面例子可以取得這些信息，並且獲得在Windows下的內存使用率.

實作過程 :
首先編寫一個 MonitorInfoBean 類，用來裝載監控的一些信息，包括物理內存、剩餘的物理內存、已使用的物理內存、內存使用率等字段，該類的代碼如下 :

- MonitorInfoBean.java : 裝載監控的信息Bean

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1. package perf.beans;  
2.   
3. public class MonitorInfoBean {  
4.       
5.     /** */  
6.     /** 可使用內存. */  
7.     private long totalMemory;  
8.   
9.     /** */  
10.     /** 剩餘內存. */  
11.     private long freeMemory;  
12.   
13.     /** */  
14.     /** 最大可使用內存. */  
15.     private long maxMemory;  
16.   
17.     /** */  
18.     /** 操作系統. */  
19.     private String osName;  
20.   
21.     /** */  
22.     /** 總物理內存. */  
23.     private long totalMemorySize;  
24.   
25.     /** */  
26.     /** 剩餘的物理內存. */  
27.     private long freePhysicalMemorySize;  
28.   
29.     /** */  
30.     /** 已使用的物理內存. */  
31.     private long usedMemory;  
32.   
33.     /** */  
34.     /** 線程總數. */  
35.     private int totalThread;  
36.   
37.     /** */  
38.     /** cpu使用率. */  
39.     private double cpuRatio;  
40.   
41.     public long getFreeMemory() {  
42.         return freeMemory;  
43.     }  
44.   
45.     public void setFreeMemory(long freeMemory) {  
46.         this.freeMemory = freeMemory;  
47.     }  
48.   
49.     public long getFreePhysicalMemorySize() {  
50.         return freePhysicalMemorySize;  
51.     }  
52.   
53.     public void setFreePhysicalMemorySize(long freePhysicalMemorySize) {  
54.         this.freePhysicalMemorySize = freePhysicalMemorySize;  
55.     }  
56.   
57.     public long getMaxMemory() {  
58.         return maxMemory;  
59.     }  
60.   
61.     public void setMaxMemory(long maxMemory) {  
62.         this.maxMemory = maxMemory;  
63.     }  
64.   
65.     public String getOsName() {  
66.         return osName;  
67.     }  
68.   
69.     public void setOsName(String osName) {  
70.         this.osName = osName;  
71.     }  
72.   
73.     public long getTotalMemory() {  
74.         return totalMemory;  
75.     }  
76.   
77.     public void setTotalMemory(long totalMemory) {  
78.         this.totalMemory = totalMemory;  
79.     }  
80.   
81.     public long getTotalMemorySize() {  
82.         return totalMemorySize;  
83.     }  
84.   
85.     public void setTotalMemorySize(long totalMemorySize) {  
86.         this.totalMemorySize = totalMemorySize;  
87.     }  
88.   
89.     public int getTotalThread() {  
90.         return totalThread;  
91.     }  
92.   
93.     public void setTotalThread(int totalThread) {  
94.         this.totalThread = totalThread;  
95.     }  
96.   
97.     public long getUsedMemory() {  
98.         return usedMemory;  
99.     }  
100.   
101.     public void setUsedMemory(long usedMemory) {  
102.         this.usedMemory = usedMemory;  
103.     }  
104.   
105.     public double getCpuRatio() {  
106.         return cpuRatio;  
107.     }  
108.   
109.     public void setCpuRatio(double cpuRatio) {  
110.         this.cpuRatio = cpuRatio;  
111.     }  
112. }  

接著編寫一個獲得當前的監控信息的接口，該類的代碼如下所示 :

- IMonitorService.java : 提供解耦合的介面

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1. package perf.proto;  
2.   
3. import perf.beans.MonitorInfoBean;  
4.   
5. public interface IMonitorService {  
6.     /** *//** 
7.      * 獲得當前監控對像. 
8.      * @return 返回監測對象 
9.      * @throws Exception 
10.      */  
11.     public MonitorInfoBean getMonitorInfoBean() throws Exception;  
12. }  

該類的實現類MonitorServiceImpl如下所示 :

- MonitorServiceImpl.java : 獲取系統訊息的實作類別

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1. package perf.utils;  
2.   
3. import perf.beans.MonitorInfoBean;  
4. import perf.proto.IMonitorService;  
5. import java.io.InputStreamReader;  
6. import java.io.LineNumberReader;  
7. import sun.management.ManagementFactory;  
8. import com.sun.management.OperatingSystemMXBean;  
9.   
10.   
11. public class MonitorServiceImpl implements IMonitorService{  
12.     public  static final int CPUTIME = 5000;  
13.     private static final int PERCENT = 100;  
14.     private static final int FAULTLENGTH = 10;  
15.     private static String PROC_CMD = System.getenv("windir")  
16.                                     + "\\system32\\wbem\\wmic.exe process get Caption,CommandLine,"  
17.                                     + "KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount";  
18.     private long[] initCpuInfo = null;  
19.       
20.     public MonitorServiceImpl(){  
21.         try{  
22.             initCpuInfo = readCpu(Runtime.getRuntime().exec(PROC_CMD));  
23.         }catch(Exception e){  
24.             e.printStackTrace();  
25.             initCpuInfo = null;  
26.         }  
27.     }  
28.       
29.     @Override  
30.     public MonitorInfoBean getMonitorInfoBean() throws Exception {  
31.         int kb = 1024;  
32.           
33.         // 可使用內存  
34.         long totalMemory = Runtime.getRuntime().totalMemory() / kb;  
35.         // 剩餘內存  
36.         long freeMemory = Runtime.getRuntime().freeMemory() / kb;  
37.         // 最大可使用內存  
38.         long maxMemory = Runtime.getRuntime().maxMemory() / kb;  
39.   
40.         OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory  
41.                 .getOperatingSystemMXBean();  
42.   
43.         // 操作系統  
44.         String osName = System.getProperty("os.name");  
45.         // 總物理內存  
46.         long totalMemorySize = osmxb.getTotalPhysicalMemorySize() / kb;  
47.         // 剩餘的物理內存  
48.         long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize() / kb;  
49.         // 已使用的物理內存  
50.         long usedMemory = (osmxb.getTotalPhysicalMemorySize() - osmxb  
51.                 .getFreePhysicalMemorySize())  
52.                 / kb;  
53.   
54.         // 獲得線程總數  
55.         ThreadGroup parentThread;  
56.         for (parentThread = Thread.currentThread().getThreadGroup(); parentThread  
57.                 .getParent() != null; parentThread = parentThread.getParent())  
58.             ;  
59.         int totalThread = parentThread.activeCount();  
60.   
61.         double cpuRatio = 0;  
62.         if (osName.toLowerCase().startsWith("windows")) {             
63.             cpuRatio = this.getCpuRatioForWindows();  
64.         }  
65.           
66.         // 返回對象  
67.         MonitorInfoBean infoBean = new MonitorInfoBean();  
68.         infoBean.setFreeMemory(freeMemory);  
69.         infoBean.setFreePhysicalMemorySize(freePhysicalMemorySize);  
70.         infoBean.setMaxMemory(maxMemory);  
71.         infoBean.setOsName(osName);  
72.         infoBean.setTotalMemory(totalMemory);  
73.         infoBean.setTotalMemorySize(totalMemorySize);  
74.         infoBean.setTotalThread(totalThread);  
75.         infoBean.setUsedMemory(usedMemory);  
76.         infoBean.setCpuRatio(cpuRatio);  
77.         return infoBean;  
78.     }  
79.       
80.     private double getCpuRatioForWindows() {  
81.         try {  
82.             if(initCpuInfo==null) return 0.0;  
83.             // 取得進程信息  
84.             //long[] c0 = readCpu(Runtime.getRuntime().exec(PROC_CMD));  
85.             //Thread.sleep(CPUTIME);  
86.             long[] c1 = readCpu(Runtime.getRuntime().exec(PROC_CMD));  
87.             if (c1 != null) {  
88.                 long idletime = c1[0] - initCpuInfo[0];  
89.                 long busytime = c1[1] - initCpuInfo[1];  
90.                 return Double.valueOf(  
91.                         PERCENT * (busytime) / (busytime + idletime))  
92.                         .doubleValue();  
93.             } else {  
94.                 return 0.0;  
95.             }  
96.         } catch (Exception ex) {  
97.             ex.printStackTrace();  
98.             return 0.0;  
99.         }  
100.     }  
101.       
102.     private long[] readCpu(final Process proc) {  
103.         long[] retn = new long[2];  
104.         try {  
105.             proc.getOutputStream().close();  
106.             InputStreamReader ir = new InputStreamReader(proc.getInputStream());  
107.             LineNumberReader input = new LineNumberReader(ir);  
108.             String line = input.readLine();  
109.             if (line == null || line.length() < FAULTLENGTH) {  
110.                 return null;  
111.             }  
112.             int capidx = line.indexOf("Caption");  
113.             int cmdidx = line.indexOf("CommandLine");  
114.             int rocidx = line.indexOf("ReadOperationCount");  
115.             int umtidx = line.indexOf("UserModeTime");  
116.             int kmtidx = line.indexOf("KernelModeTime");  
117.             int wocidx = line.indexOf("WriteOperationCount");  
118.             long idletime = 0;  
119.             long kneltime = 0;  
120.             long usertime = 0;  
121.             while ((line = input.readLine()) != null) {  
122.                 if (line.length() < wocidx) {  
123.                     continue;  
124.                 }  
125.                 // 字段出現順序：Caption,CommandLine,KernelModeTime,ReadOperationCount,  
126.                 // ThreadCount,UserModeTime,WriteOperation  
127.                 String caption = Bytes.substring(line, capidx, cmdidx - 1).trim();  
128.                 String cmd = Bytes.substring(line, cmdidx, kmtidx - 1).trim();  
129.                 if (cmd.indexOf("wmic.exe") >= 0) {  
130.                     continue;  
131.                 }  
132.                 // log.info("line="+line);  
133.                 if (caption.equals("System Idle Process")  
134.                         || caption.equals("System")) {  
135.                     idletime += Long.valueOf(  
136.                             Bytes.substring(line, kmtidx, rocidx - 1).trim())  
137.                             .longValue();  
138.                     idletime += Long.valueOf(  
139.                             Bytes.substring(line, umtidx, wocidx - 1).trim())  
140.                             .longValue();  
141.                     continue;  
142.                 }  
143.   
144.                 kneltime += Long.valueOf(  
145.                         Bytes.substring(line, kmtidx, rocidx - 1).trim())  
146.                         .longValue();  
147.                 usertime += Long.valueOf(  
148.                         Bytes.substring(line, umtidx, wocidx - 1).trim())  
149.                         .longValue();  
150.             }  
151.             retn[0] = idletime;  
152.             retn[1] = kneltime + usertime;  
153.             return retn;  
154.         } catch (Exception ex) {  
155.             ex.printStackTrace();  
156.         } finally {  
157.             try {  
158.                 proc.getInputStream().close();  
159.             } catch (Exception e) {  
160.                 e.printStackTrace();  
161.             }  
162.         }  
163.         return null;  
164.     }  
165. }  

該實現類中需要用到一個自己編寫byte的工具類，該類的代碼如下所示 :

- Bytes.java : 解決 String.subString() 處理中文的問題 (將中文試為一個byte)

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1. package perf.utils;  
2.   
3. public class Bytes {  
4.     public static String substring(String src, int start_idx, int end_idx){  
5.         byte[] b = src.getBytes();  
6.         String tgt = "";  
7.         for(int i=start_idx; i<=end_idx; i++){  
8.             tgt +=(char)b[i];  
9.         }  
10.         return tgt;  
11.     }  
12. }  

測試結果 :
測試我們可以建立一個 MonitorServiceImpl 類別的實例, 在一建立時例後 MonitorServiceImpl 會立即取得當下的 CPU 相關初始訊息. 接著我們讓當前線程 Sleep 6 秒後在呼叫 getMonitorInfoBean() 函式已取的相關系統訊息, 測試代碼如下 :

- TMain.java : 測試類別

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1. package perf.test;  
2.   
3. import perf.beans.MonitorInfoBean;  
4. import perf.utils.MonitorServiceImpl;  
5.   
6. public class TMain {  
7.     public static void main(String args[])  
8.     {  
9.         MonitorServiceImpl MSImpl = new MonitorServiceImpl();  
10.         try {  
11.             Thread.sleep(MonitorServiceImpl.CPUTIME);  
12.             MonitorInfoBean bean = MSImpl.getMonitorInfoBean();  
13.             System.out.println("OSName: "+bean.getOsName());  
14.             System.out.println("CPU Ratio: "+bean.getCpuRatio());  
15.             System.out.println("Available Mem in JVM: "+String.valueOf(bean.getTotalMemory()/1000.0)+" MB");  
16.             System.out.println("Free Mem in JVM: "+bean.getFreeMemory()/1000.0+" MB");  
17.             System.out.println("Max Available Mem for JVM: "+bean.getMaxMemory()/1000.0+" MB");  
18.             System.out.println("============================");  
19.             System.out.println("Total Pyysical Mem Size: "+bean.getTotalMemorySize()/1000.0+" MB");  
20.             System.out.println("Total Physical Free Mem: "+bean.getFreePhysicalMemorySize()/1000.0+" MB");  
21.             System.out.println("Total Physical Used Memory: "+bean.getUsedMemory()/1000.0+" MB");  
22.             System.out.println("============================");  
23.             System.out.println("Total Thread in Java: "+bean.getTotalThread());  
24.         } catch (Exception e) {           
25.             e.printStackTrace();  
26.         }  
27.           
28.     }  
29. }  

執行結果 :

OSName: Windows 7
CPU Ratio: 12.0
Available Mem in JVM: 79.296 MB
Free Mem in JVM: 55.281 MB
Max Available Mem for JVM: 932.096 MB
============================
Total Pyysical Mem Size: 4191.412 MB
Total Physical Free Mem: 1311.06 MB
Total Physical Used Memory: 2880.352 MB
============================
Total Thread in Java: 5

補充說明 :
* [Windows 技巧] wmic 使用簡介

wmic 是 Microsoft Windows Management Instrument 的縮寫. 提供了 Console mode 一個強而有力的 administrator 管理工具. 包或系統管理, 遠端主機訊息獲取到你想不到的更改主機名稱等功能都可以達成. 而 wmic 可以在路徑 C:\Windows\System32\wbem 下找到 (wmic.exe)...

This message was edited 3 times. Last update was at 26/05/2011 15:07:17